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Messages - CR Backup Admin

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646
Software & Accessories / Re: 580EX II Faulty by Design?
« on: February 20, 2011, 11:52:59 AM »
After seeing all the comments about what a great report this was, I read it this morning.  I was not impressed.

 I managed a electrical component lab at a large aerospace company, where we did high voltage arcing tests for components that went into spacecraft and aircraft.  Arcing is a big concern, whether it is from corona or from chaffing of wiring, or from secondary effects of lightening strikes.

Nothing I saw in the report hinted at any recognition of high voltage expertise of the testers, it did not identify them or their level of experience, but from the way it was written, it sounded like some low voltage engineers or technicians who were out of their element playing around in a lab that was not equiped either personnel wise or equipment wise to determine a root cause..

They seemed suprised that the arcing started again when they repaired the electronics.  This indicated a failure to understand the mechanics of dry arc-tracking.  Presumably wet arc-tracking was not involved, since there was no indication of a fluid being involved.

I'm not going to analyze the problem from a distance, but I did not see anything that approached the type of testing or even recognition of what the likely first thing I'd look for happened.

Determining the root cause for arcing is very difficult, and requires a high level of experience with high voltage work.

647
Canon General / Re: Photographer Profile: Drew "Rukes" Ressler
« on: February 19, 2011, 10:32:42 PM »
Sometimes people seem to join just to see how far they can push the moderator.  They contribute nothing positive, and have zero credibility. 

A forum member who has posted over a period of time and contributed positive things to the forum builds up Karma. I give them some leeway to post criticism because they have demonstrated some knowledge or expertise of photography.

I read every post, and delete posts that are objectionable as far as I'm concerned.

In this case, I've been pushed too far!    ZAP !!


648
Software & Accessories / Re: Using Canon Battery Pack in Speedlite Flashes
« on: February 19, 2011, 02:51:58 PM »
The reason the Li-on battery packs are not advisable for use in a flash is the high rate of discharge required to recharge a flash unit after firing it.  Li-on is great for low current applications, but not for high current.

1.  The effective usable capacity would be lower before the cells electronics shut it down

2.  The battery would age very quickly and die much sooner.

A battery pack designed for high current by placing several li-on batteries in parallel couldwork, but thats a whole different design.



Here is a little more of the technical discussion quoted from wikipedia.

Internal resistanceThe internal resistance of standard (Cobalt) lithium-ion batteries is high compared to both other rechargeable chemistries such as nickel-metal hydride and nickel-cadmium, and LiFePO4 and lithium-polymer cells

Internal resistance increases with both cycling and age.   Rising internal resistance causes the voltage at the terminals to drop under load, which reduces the maximum current draw. Eventually increasing resistance means that the battery can no longer operate for an adequate period.

649
EOS Bodies / Re: 5dmkii june '10 firmware update for manual film control
« on: February 19, 2011, 11:43:29 AM »
Fadein and fadeouts are best done in post.  Doing it with a camera lens is not going to be very satisfactory.  In post production, you can get it timed to the specific frame and can redo it until it comes out the way that looks best.

650
EOS Bodies / Re: Something Coming March 1?
« on: February 18, 2011, 12:54:50 PM »
So, if you can wait about 6 months or so, the price will come down significantly and you'll sure what you'll get. That's what I did when 7D came out.

I ordered my 5D MK II minutes after the announcement well over 2 years ago, it had no issues and the price for a new one is still the same.

651
EOS Bodies / Re: 5dmkii june '10 firmware update for manual film control
« on: February 18, 2011, 12:50:14 PM »
The 5D MK II will let you change the aperture during shooting if you are using full manual control.  The image will get darker or brighter, so if you are trying to change depth of field, you will also need to change the accordingly.

The 5D MK II is not a camcorder, and Canon specifically recommends that you do not change the aperture during shooting, but they allow you to do it if you want.

652
EOS Bodies / Re: 60D vs 7D with FF in the near future:
« on: February 17, 2011, 08:59:28 PM »
Does the 60D have the function like the 5D MII (I know the 7D does not) where on live view the viewfinder is automatically shut? Something inside of me still says get the 7D.

My 5D MK II does not have any automatic shutter for the eyepiece, there is a external eyepiece cover you must put over it to block light.  Same for 7D and all the Rebels.

For those cameras with liveview, the mirror comes up and blocks most of the light in the eyepiece, but for long exposure times, I'd still cover it.

653
Software & Accessories / Re: 580EX II Faulty by Design?
« on: February 17, 2011, 07:46:01 PM »
I would think that the higher power output of the 580 EX II requires the best possible cooling.  PW needs those shields over the flash so their faulty control unit will work further than 30 ft away. 

Heat destroys electronics, and is likely taking its toll.

Fortunately, I stayed away from the new PW units when it became apparent that they would not work for more than a few feet, and that they did not work with the 5D MK II.  Eventually, they figured out how to make them work with a 5D MK II, but the blanket wrapped around the flash is pure hokum.

654
Software & Accessories / Re: 580EX II Faulty by Design?
« on: February 17, 2011, 03:43:41 PM »
I've been using three 580 EX II's without a PW for years with no issues.  The PW's though have had plenty of problems, and require a circuit change in the 580 EX II to reduce RF and increase the range slightly, or a wierd wrap around device.

655
EOS Bodies / Re: 1d Mkiii vs 7d... I know, I know
« on: February 17, 2011, 11:33:32 AM »
I have a 1D3 as a backup to my 1Ds3. I have a chance to sell it for a couple grand, and was thinking of doing so and getting the 7d... Will the iq be as good or better? I shoot with all L glass, for magazine and newspaper print primarily. I'm looking to keep the fps versatility and hopefully increase low light / high ISO over the 1D's. I know the 1D4 would be a preffered choice, but I'd rather wait for the next 1Ds before spending that much.  I klnow this has been covered on other forums, but couldn't find a recent rundown.  Thanks.

I sold my 1D MK II and bought a 7D.  I returned it right away.  Then I bought a 1D MK III.  Its a much better camera overall.

656
EOS Bodies / Re: 60D & 7D Rebates coming February 20
« on: February 17, 2011, 11:22:53 AM »
Canon has rebates, late spring and late fall.  This seems to be one of the short term in-between rebates.  Probably to soften the recent increase in lens pricing.

657
EOS Bodies / Re: 60D & 7D Rebates coming February 20
« on: February 16, 2011, 08:51:15 PM »
They were in the fall rebates as well.  it probably has more to do with nikon rebates and the need to match them.

The 60d is a new model, and 7D is not that old.  They won't be replaced this year.

658
Lenses / Re: EF-S L Lenses
« on: February 16, 2011, 05:49:35 PM »
Well a blue ring would look nice.  :D

At one time, Canon sold screw on colored rings to customize the color of your lens, and blue was one of the colors.

http://vistek.ca/store/CameraLenses/235104/canon-ring-kit-rakdc1-for-g9.aspx

Then, there was the much vaunted Canon 20-400mm f/2.8 zoom which had a blue ring.

http://balkophoto.com/blog/?p=26  ;)

659
EOS Bodies / Re: 60D & 7D Rebates coming February 20
« on: February 16, 2011, 03:45:15 PM »
Tranfer rates are determined by the weakest component in the path and I do not believe that the camera tech/hardware is able to push data at those rates (yet and probably intentional).  This greatly diminshes the memory card rating importance as the specified transfer rated are not (and probably never will be) achieved in actual usage.  There is probably not that much difference in use between a mid level and a high level card (say 60 and 100 MB/s)

Also the manufacturers tend to exagurate (a little) and actual vs. theoretical in real world scenarios are (quite) different.

Some real world testing here. 

The fastest camera / memory combination I saw during a quicl look was the Sony A=900 at 35.5 MB/sec.  Thats pretty fast.  The Canon 5D MK II manages 32.6 MB/sec.  He did not test any cameras with SD memory.

For flash memory, CF card to computer transfers were tested 97.3 MB/sec with the fastest reader and cards.

http://www.robgalbraith.com/bins/reader_report_multi_page.asp?cid=6007-9392

SD memory doesn't really come close, with about 25 MB/sec being the fastest card to computer.

660
Lenses / Re: EF-S 15-60 f/2.8 IS [CR1]
« on: February 16, 2011, 03:25:36 PM »
One of the reasons you might want to use a faster shutter speed with a 7d is the higher pixel density.  Even a tiny movement will show blur at the pixel level, while the much larger pizels of a FF may not get smeared with the same amount of movement. 

However, the resultant image viewed at the same print size won't show it, just peeping at 1:1 magnification.

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